The proposed work will be a continuation of our program sponsored by the USPHS during the last year. We have demonstrated that severe biochemical alterations occur in heart muscle of dogs exposed to alcohol from a period of 3 months to 2 years. These changes are not accompanied by a decline in contractility. It is the purpose of this study, using a refined method of isometric and isotonic contraction of isolated heart muscle fibers (Julian, Huxley) to investigate whether any small alteration in contractility can be discovered with this refined instrumentation. If these changes occur, they would be correlated with processes connected with electro-mechanical coupling. If no relationship can be found between the biochemical changes and the contractility of the heart muscle, we will extend our studies to the acute effects of alcohol on the heart muscle, in which marked changes in contractiliy have been discovered. These studies could reveal the reasons why prolonged administration of alcohol for several years fails to alter contractility, while the acute administration results in rapid decline of contractility. BIBLIOGRAPHIC REFERENCES: Bing, R.J., Tillmanns H., Fauvel, J-M, Seeler, K., and Mao J.C: The Effect of Prolonged Alcohol Administration on calcium transport in heart muscle. Circ. Res. 35:33-38, 1975. Bing, R.J., Tillmanns, H., Ikeda, S.: Metabolic effects of Alcohol on the Heart. New York Academy of Sciences 252:243-249, April 1975.